1. Field of the Invention
This invention relates to a method for making splice indicating holes through roll of photographic paper, which are to be loaded into an automatic printer. This invention particularly relates to a method for making splice indicating holes through a wide photographic paper web before the photographic paper web is slit into a plurality of narrow webs of photographic paper. This invention also relates to an apparatus for carrying out the method.
2. Description of the Prior Art
In general, rolls of photographic paper, which are to be loaded into an automatic printer, are prepared by slitting a wide photographic paper web into a plurality of narrow webs and winding up predetermined lengths of the slit webs around cores. For this purpose, by way of example, a slitting machine disclosed in, for example, U.S. Pat. No. 4,629,139 may be used. In cases where the length of a photographic paper web becomes shorter than the predetermined length, a leading end of a new photographic paper web is spliced to the tail end of the photographic paper web which is shorter than the predetermined length. For this purpose, by way of example, a splicing apparatus disclosed in, for example, Japanese Patent Publication No. 1(1989)-41981 may be used. In such cases, the rolls of photographic paper, which have been obtained by slitting the spliced photographic paper web, have splices at which the two photographic paper webs were spliced. In the automatic printer, the splices are removed automatically such that they may not be used.
Therefore, it has been stipulated in an international standard (ISO TC42/WG8) that rolls of photographic paper must be provided with splice indicating holes from which the presence of splices is to be detected automatically. The splice indicating hole is located on the center line of the roll of photographic paper and at a position spaced a predetermined distance from the splice of photographic paper.
Heretofore, in order for splice indicating holes to be made, a number of sets of punches and dies, which number is equal to the number of narrow webs into which a photographic paper web is slit, are located side by side in the width direction of the photographic paper web and in the vicinity of the photographic paper web, which is conveyed from a web splicing apparatus to a slitting apparatus. When a splice between two photographic paper webs reaches a predetermined position, the conveyance of the web is ceased, and the punches and the dies are operated together.
FIG. 10 is a perspective view showing an example of a conventional perforating apparatus for making splice indicating holes through a photographic paper web. FIG. 11 is a perspective view showing part of the conventional perforating apparatus of FIG. 10. With reference to FIGS. 10 and 11, a perforating apparatus 50 comprises a number of sets of punches 54, 54, . . . and dies 55, 55, . . . , which number is equal to the number of narrow webs into which a photographic paper web 53 is slit. The multiple sets of the punches 54, 54, . . . and the dies 55, 55, . . . are located side by side in the width direction of the photographic paper web 53 and in the vicinity of the photographic paper web 53, which is conveyed from a web splicing apparatus 51 to a slitting apparatus 52. The photographic paper web 53 is conveyed through the space between the punches 54, 54, . . . and the dies 55, 55, . . . The punches 54, 54, . . . are moved together up and down in FIG. 11 by cams 58, 58, . . . which are secured to a shaft 57. The shaft 57 is rotated by a motor 56. The punches 54, 54, . . . fit into die cavities 55a, 55a, . . . of the dies 55, 55, . . . with the photographic paper web 53 intervening therebetween. In this manner, a plurality of splice indicating holes 59, 59, . . . are simultaneously made through the photographic paper web 53. In FIG. 10, reference numeral 60 represents a web splice. The photographic paper web 53 is slit later along broken lines 61, 61, . . . .
In cases where the multiple sets of punches and dies described above are used, when the width, into which the photographic paper web is to be slit, is changed, the intervals between the respective sets of the punches and the dies in the width direction of the photographic paper web are adjusted again in accordance with the new value of the width, into which the photographic paper web is to be slit. Alternatively, the previous unit of the multiple sets of the punches and the dies is replaced by a new unit of multiple sets of punches and dies, in which new unit the intervals between the respective sets of the punches and the dies in the width direction of the photographic paper web correspond to the new value of the width, into which the photographic paper web is to be slit.
However, with the conventional perforating method wherein the punches and dies described above are used, it is necessary for the conveyance of the photographic paper web to be ceased temporarily when splice indicating holes are made through the photographic paper web. Therefore, loss of time occurs during the operation, and the efficiency with which the slitting operation is carried out cannot be kept high.
Also, in cases where the intervals between the respective sets of the punches and the dies are adjusted again or the unit of the multiple sets of the punches and the dies is replaced by a new unit of multiple sets of punches and dies each time the width, into which the photographic paper web is to be slit, is changed, the slitting operation must be ceased. Therefore, the productivity cannot be kept high.
Additionally, in cases where the unit of the multiple sets of the punches and the dies is replaced by a new unit of multiple sets of punches and dies, it is necessary for several units to be prepared. Therefore, the cost of the perforating apparatus cannot be kept low. The cost of the perforating apparatus becomes higher when the width, into which the photographic paper web is to be slit, is changed to a wider variety of values.